A 10-year investigation of bandicoot specimens held in museums around the world has uncovered two previously unrecognized species and several new subspecies within the genus Isoodon, commonly known as short-nosed or brown bandicoots. The study, published in the Australian Journal of Taxonomy, also changes the known historical distribution of the quenda, or southeastern brown bandicoot.
Researchers examined hundreds of specimens, combining DNA analysis with detailed skull measurements to reassess relationships among bandicoot populations in Australia and New Guinea. The project began in 2016, when researchers compared specimens collected more than a century ago in European and US museums with material held in Australian collections.
One of the newly recognized species is the little brown bandicoot, Isoodon microtis, from South Australia. The researchers believe it became extinct about a century ago, before it had been scientifically identified. Museum specimens had remained unrecognized for generations until the study established that the animal was sufficiently distinct from other bandicoots to receive species status.
The research also determined that the New Guinea brown bandicoot, Isoodon moresbyensis, is a separate species rather than a subspecies of the northern brown bandicoot, Isoodon macrourus.
The revision significantly changes the picture of bandicoot diversity in South Australia. Earlier classifications indicated that the southern brown bandicoot was the only species present in the state. The new analysis found evidence that South Australia once supported three species: the southern brown bandicoot, the extinct little brown bandicoot and the quenda, Isoodon fusciventer.
The quenda had generally been regarded as a Western Australian species, but the museum evidence shows that it formerly occurred around Adelaide, Kangaroo Island and the Nuyts Archipelago. That finding extends its known historical range substantially eastward.
Researchers also described two new subspecies of the golden bandicoot, four quenda subspecies and a new subspecies of the northern brown bandicoot from Cape York in Queensland. Together, the results indicate that Australia once supported a greater diversity of bandicoot forms than previously recognized.
The findings could affect conservation decisions because species classification is used to assess extinction risk and guide the allocation of conservation resources. The quenda’s broader historical range may mean it is less threatened overall than previously thought, although its South Australian populations remain small and need continued protection. In contrast, the revised distribution of the endangered southern brown bandicoot is more restricted, potentially indicating a greater conservation risk.
Bandicoots are rabbit-sized marsupials found in Australia and New Guinea. They have pointed snouts, large hind legs and short tails, and forage by digging with their front paws. Most eat a mixture of fungi, roots, insects and other small invertebrates.
The researchers are now turning to long-nosed bandicoots in the genus Perameles. Five species in that group have disappeared since European settlement, and the team expects museum collections to provide further evidence about Australia’s overlooked natural history.
Sources: Phys.org.